BLADE ANGLE POSITION FEEDBACK SYSTEM WITH EXTENDED MARKERS
A blade angle feedback assembly for an aircraft-bladed rotor and an aircraft-bladed rotor system are provided. The rotor is rotatable about a longitudinal axis and has an adjustable blade pitch angle. A feedback device is coupled to rotate with the rotor , the feedback device having a root surface having an edge. At least one position marker extends from the root surface and extends laterally beyond the edge. At least one sensor is mounted adjacent the feedback device and configured to detect a passage of the at least one position marker as the feedback device rotates about the longitudinal axis.
The present disclosure relates generally to engines, and more specifically to blade angle position feedback systems.
BACKGROUND OF THE ARTOn featherable aircraft propeller systems, it is desirable to accurately measure the propeller blade pitch (or beta) angle to ensure that the blade angle is controlled according to the engine power set-point requested, such as in reverse and low pitch situations, also known as the beta operating region. For this purpose, some propeller feedback systems use a beta or feedback device, sometimes referred to as a phonic wheel, which rotates with the engine. The feedback device has multiple readable raised markers disposed on an outer surface thereof, and a sensor can be used to measure the rotation of the feedback device via the markers, providing a proxy value for the rotational velocity of the engine, as well as measure blade angle. Existing feedback devices are however vulnerable to a so-called “edge-effect” that leads to an increase in reading error as the sensor approaches the edges of the feedback device.
Therefore, improvements are needed.
SUMMARYIn accordance with a broad aspect, there is provided a blade angle feedback assembly for an aircraft-bladed rotor, the rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle. The assembly comprises a feedback device coupled to rotate with the rotor , the feedback device having a root surface having an edge, at least one position marker extending from the root surface and extending laterally beyond the edge, and at least one sensor mounted adjacent the feedback device and configured to detect a passage of the at least one position marker as the feedback device rotates about the longitudinal axis.
In accordance with another broad aspect, there is provided an aircraft-bladed rotor system, comprising a rotor rotatable by a shaft about a longitudinal axis, the rotor having blades with adjustable blade pitch angle, and a feedback device coupled to rotate with the rotor, the feedback device having a root surface having an edge, at least one position marker extending from the root surface and extending laterally beyond the edge.
In some embodiments, the root surface has a first edge and a second edge opposite the first edge, and the at least one position marker extends axially from a first end to a second end, at least one of the first end and the second end extending laterally beyond a corresponding at least one of the first edge and the second edge.
In some embodiments, the at least one sensor is configured to detect, as the feedback device rotates about the longitudinal axis, a change in magnetic flux caused by passage of the at least one position marker in a sensing zone of the at least one sensor, the at least one of the first end and the second end extending laterally beyond the at least one of the first edge and the second edge resulting in an increase in a density of the magnetic flux as the feedback device is displaced along the longitudinal axis.
In some embodiments, the at least one sensor is mounted adjacent the feedback device between the first edge and the second edge, the first end of the at least one position marker extending laterally beyond the first edge and the second end of the at least one position marker extending laterally beyond the second edge.
In some embodiments, the at least one sensor is mounted adjacent a given one of the first edge and the second edge, the at least one position marker extending laterally beyond the other one of the first edge and the second edge.
In some embodiments, the feedback device comprises at least one support member configured to extend away from the at least one of the first edge and the second edge and to support the at least one of the first end and the second end thereon.
In some embodiments, the at least one of the first end and the second end is substantially parallel to the corresponding at least one of the first edge and the second edge.
In some embodiments, the at least one position marker comprises a first plurality of projections extending from the root surface and oriented substantially parallel to the longitudinal axis and at least one second projection extending from the root surface and positioned between two adjacent first projections, the first plurality of projections circumferentially spaced from one another and the at least one second projection disposed on the root surface at an angle relative to the first plurality of projections, and further wherein the first plurality of projections and the at least one second projection extend laterally beyond the at least one of the first edge and the second edge.
Features of the systems, devices, and methods described herein may be used in various combinations, in accordance with the embodiments described herein.
Reference is now made to the accompanying figures in which:
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
DETAILED DESCRIPTIONThe turbine section 118 comprises a compressor turbine 120, which drives the compressor assembly and accessories, and at least one power or free turbine 122, which is independent from the compressor turbine 120 and rotatingly drives a rotor shaft (also referred to herein as a propeller shaft or an output shaft) 124 about a propeller shaft axis ‘A’ through a reduction gearbox (RGB) 126. Hot gases may then be evacuated through exhaust stubs 128. The gas generator of the engine 110 comprises the compressor section 114, the combustor 116, and the turbine section 118.
A rotor, in the form of a propeller 130 through which ambient air is propelled, is hosted in a propeller hub 132. The rotor may, for example, comprise the propeller 130 of a fixed-wing aircraft, or a main (or tail) rotor of a rotary-wing aircraft such as a helicopter. The propeller 130 may comprise a plurality of circumferentially-arranged blades connected to a hub by any suitable means and extending radially therefrom. The blades are also each rotatable about their own radial axes through a plurality of blade angles, which can be changed to achieve modes of operation, such as feather, full reverse, and forward thrust.
Rotation of the output shaft 124 is facilitated by one or more bearing assemblies (not illustrated), which can be disposed within the RGB 126 or at any other suitable location. The bearing assemblies are electrically isolating during operation due to an oil film which is present at the bearing assemblies where they rotate. As the output shaft 124 rotates, electrical charge generates on the output shaft 124. For example, the output shaft 124 can be struck by lightning or other electrical discharges, or can be subjected to triboelectric charge accumulation. Because of the electrically isolating nature of the bearing assemblies, the output shaft 124 can accumulate an electric potential difference vis-a-vis a casing (not shown) of the engine 110. If the electric potential reaches or surpasses the breakdown threshold of the oil film in the bearing assemblies, the accumulated charge can dissipate via dielectric breakdown in the bearing assemblies. This can cause electrical discharge damage (EDD) to the bearing assemblies.
With reference to
In some embodiments, the system 200 provides for detection and measurement of rotational velocity of one or more rotating elements of the engine 110 and of propeller blade angle on propeller systems, such as the propeller 130 of
The system 200 comprises an annular member 204 and one or more sensors 212 positioned proximate the annular member 204. Annular member 204 (referred to herein as a feedback device) has a plurality of detectable features (also referred to as position markers or teeth) 202 disposed thereon for detection by sensor(s) 212. In some embodiments, the feedback device 204 is mounted for rotation with propeller 130 and to move axially with adjustment of the blade angle of the blades of the propeller 130, and the one or more sensors 212 are fixedly mounted to a static portion of the engine 110. In other embodiments, the one or more sensors 212 are mounted for rotation with propeller 130 and to move axially with adjustment of the blade angle of the blades of the propeller 130, and the feedback device 204 is fixedly mounted to a static portion of the engine 110.
The system 200 also includes a controller 220 communicatively coupled to the one or more sensors 212. The sensor(s) 212 are configured for producing a sensor signal which is transmitted to or otherwise received by the controller 220, for example via a detection unit 222 thereof. The sensor signal can be an electrical signal, digital or analog, or any other suitable type of signal. In some embodiments, the sensor(s) 212 produce a signal pulse in response to detecting the presence of a position marker 202 in a sensing zone of the sensor 212. For example, the sensor 212 is an inductive sensor that operates on detecting changes in magnetic flux, and has a sensing zone which encompasses a circular or rectangular area or volume in front of the sensor 212. When a position marker 202 is present in the sensing zone, or passes through the zone during rotation of the feedback device 204, the magnetic flux in the sensing zone is varied by the presence of the position marker 202, and the sensor 212 can produce a signal pulse, which forms part of the sensor signal. Accordingly, the position markers 202 may be made of any suitable material (e.g., a ferromagnetic material, Mu-Metal, or the like) which would cause the passage of the position markers 202 near the sensor 212 to provide a change in magnetic permeability within the magnetic field generated by the sensor 212.
In the example illustrated in
In some embodiments, a single sensor 212 is mounted in close proximity to the feedback device 204 and the position markers 202. In some other embodiments, in order to provide redundancy as well as dual-signal sources at multiple locations, one or more additional sensors, which may be similar to the sensor 212, are provided. For example, an additional sensor 212 may be mounted in a diametrically opposite relationship, or at any angle, relative to the position markers 202, which extend away from the feedback device 204 and towards the sensor(s) 212. In yet another embodiment, several position markers 202 may be spaced equiangularly about the perimeter of the feedback device 204. Other embodiments may apply.
Wth additional reference to
The position markers 202 may comprise a plurality of first projections (not shown) arranged along a direction substantially transverse to the opposing faces and substantially equally spaced from one another on the root surface 304. The position markers 202 may also comprise one or more second projections (not shown) each positioned between two adjacent first projections. Each second projection is illustratively oriented along a direction, which is at an angle relative to the direction along which the first projections are arranged. The angle can be any suitable value between 1° and 89°, for example 30°, 45°, 60°, or any other value, as appropriate. It should be noted, however, that in some other embodiments the second projection(s) can be co-oriented with the first projections. It should also be noted that in some embodiments, each second projection can be substituted for a groove or inward projection, as appropriate. In addition, in some embodiments, the feedback device 204 includes only a single second projection while, in other embodiments, the feedback device 204 can include more than one second projection. In the latter case, the second projections can be oriented along a common orientation or along one or more different orientations and each second projection can be located at substantially a midpoint between two adjacent first projections or can be located close to a particular one of two adjacent first projections.
In one embodiment, the position markers 202 are integrally formed with the feedback device 204 so that the feedback device 204 may have a unitary construction. In another embodiment, the position markers 202 are manufactured separately from the feedback device 204 and attached thereto using any suitable technique, such as welding or the like.
It should also be noted that, although the present disclosure focuses primarily on embodiments in which the position markers 202 are projections, other embodiments are also considered. The position markers 202 may, for example, comprise one or more of protrusions, teeth, walls, voids, recesses, and/or other singularities. For instance, in some embodiments, the position markers 202 may be embedded in the circular disk portion of the feedback device 204, such that the feedback device 204 has a substantially smooth or uniform root surface 304. A position marker 202 can then be a portion of the feedback device 204 which is made of a different material, or to which is applied a layer of a different material. The position markers 202 may then be applied to the root surface 304, for instance as strips of metal or other material for detection by the sensor 212, which can be an inductive sensor capable of sensing changes in magnetic flux (as discussed above) or any other suitable sensor such as a Hall sensor or a variable reluctance sensor. Still other embodiments are considered.
The signal pulses produced by the sensor 212, which form part of the electrical signal received by the control system 220, can be used to determine various operating parameters of the engine 110 and the propeller 130. The regular spacing of the first projections can, for example, be used to determine a speed of rotation of the feedback device 204. In addition, the second projection(s) can be detected by the sensor 212 to determine a blade angle of the propeller 130.
Wth continued reference to
As depicted in
Referring now to
As the extension of material provided on the position markers 202 rotates past the sensor 212, the presence of the added material will make detection possible even when the axial position of the feedback device 204 is farthest away from the sensor 212. In this manner, the magnetic flux path is continuous when the feedback device 204 moves axially away from the sensor 212. In other words, the magnetic flux path is extended and this magnetic path extension provides a low reluctance magnetic return path to close the magnetic circuit. The magnetic path extension further provides a permeable material extension which reroutes the path of the magnetic flux lines and increases the magnetic flux density at the edges of the feedback device 204, as the feedback device 204 moves axially along axis A. This increases the sensor signal and may in turn mitigate (i.e. reduce) edge-related effects, thereby allowing accurate detection of the position markers 202. The material extension illustratively reduces the loss of magnetic flux density at the edges 3021 and 3022 by essentially moving the at least one of the edges 3021, 3022 beyond the sensing zone of the sensor 212.
In one embodiment, the extrusion of material is integral with the feedback device 204, whereby the extension is machined from solid, leaving the overhung material extensions. In another embodiment, the material extension is added to the feedback device 204 by welding. Other embodiments may apply that include manufacturing methods such as additive manufacturing, casting, forging, extrusion, powder metallurgy, blanking, broaching, milling, grinding and other suitable methods.
In one embodiment illustrated in
The feedback device 204 also includes at least one supplementary projection 420 which is positioned between two adjacent ones of the projections 410. In the embodiment depicted in
In some embodiments, the feedback device 204 includes only a single supplementary projection 420. In other embodiments, the feedback device 204 can include two, three, four, or more supplementary projections 420. In embodiments in which the feedback device 204 includes more than one supplementary projection 420, the supplementary projections can all be oriented along a common orientation, for instance direction ‘E’, or can be oriented along one or more different orientations. The projection 420 can be located at substantially a midpoint between two adjacent projections 410, or, as shown in
In order to reduce any edge-related effects, the projections 410 and 420 are configured to extend laterally (along the direction ‘D’ and along the direction ‘E’, respectively) beyond at least one of the edges 3021, 3022 (i.e. beyond a plane formed by at least one of the faces 3011, 3012 of the feedback device 204). The position markers 202 illustratively extend laterally beyond the same edge(s) 3021, 3022. In particular and as shown in
In particular, the distance of the terminations 412, 414 (i.e. the distance by which the projections 410, 420 extend away from the edge 3021 and/or the edge 3022) is illustratively specific to the application, the parameters (e.g. engine configuration) specific to that application, the distance of the sensor 212 relative to the feedback device 204, the geometry of the feedback device 204, and the beta error experienced by the feedback system. In one embodiment, the material is added to the termination 412 and/or the termination 414 such that the projections 410, 420 extend past the sensing zone of the sensor 212. The limiting factors to the extension(s) may relate to stress limitations, therefore, in some embodiments, the extension(s) may be supported by a large radius below the tooth extension, as discussed further below. In another embodiment the terminations extend only as far as required to eliminate the beta error.
It should also be understood that, although the terminations 412, 414 are shown in
In the embodiment shown in
The determination as to the edge(s) 3021, 3022 beyond which the projections 410, 420 extend illustratively depends on the location (i.e. the distance) of the sensor 212 relative to the feedback device 204. Indeed, it is desirable to provide the extrusion of material adjacent the edge(s) 3021, 3022 furthest away from a location where the sensor 212 is positioned. For example, for a feedback device assembly having a sensor 212 located adjacent a given one of the edges (e.g., edge 3021), it may be desirable to extend the projections 410, 420 beyond the opposite edge (e.g., edge 3022. If the sensor 212 is positioned between the edges 3021, 3022, e.g., substantially halfway, it may in turn be desirable to extend the projections 410, 420 beyond both edges 3021, 3022. Additional factors, such as the amount of beta error, may also come into play when determining the edge(s) 3021, 3022 beyond which the projections 410, 420 extend. For example, if a higher beta error is exhibited on one side of the feedback device 204, material extension may be added to balance the readings or eliminate the beta error all together. Available space according to clearances and tolerance stackup of the feedback system may also impact the determination as to which edge 3021, 3022 to extend. Additionally, the determination of which edge 3021, 3022 to extend may be related to the accuracy required by the feedback system and the extension may be employed as a means of achieving the required accuracy.
In addition and as shown in
In some embodiments, the base material of the feedback device 204 may also be extended beyond the edge 3021 and/or the edge 3022 in order to provide support for the extrusion of material that extends the projections 410, 420 beyond the edge 3021 and/or the edge 3022. For example, and as shown in
From the above description, it can be seen that, in one embodiment, the feedback device 204 may be configured to allowing for the sensor 212 to be positioned near or at the edges 3021, 3022 of the feedback device 204 while accurately detecting the passage of the position markers 202, thereby mitigating any edge-related effects that may influence the sensor 212.
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure.
Various aspects of the systems and methods described herein may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Although particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects. The scope of the following claims should not be limited by the embodiments set forth in the examples, but should be given the broadest reasonable interpretation consistent with the description as a whole.
Claims
1. A blade angle feedback assembly for an aircraft-bladed rotor, the rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle, the assembly comprising:
- a feedback device coupled to rotate with the rotor, the feedback device having a root surface having an edge;
- at least one position marker extending from the root surface and extending laterally beyond the edge; and
- at least one sensor mounted adjacent the feedback device and configured to detect a passage of the at least one position marker as the feedback device rotates about the longitudinal axis.
2. The feedback assembly of claim 1, wherein the root surface has a first edge and a second edge opposite the first edge, and the at least one position marker extends axially from a first end to a second end, at least one of the first end and the second end extending laterally beyond a corresponding at least one of the first edge and the second edge.
3. The feedback assembly of claim 2, wherein the at least one sensor is configured to detect, as the feedback device rotates about the longitudinal axis, a change in magnetic flux caused by passage of the at least one position marker in a sensing zone of the at least one sensor, the at least one of the first end and the second end extending laterally beyond the at least one of the first edge and the second edge resulting in an increase in a density of the magnetic flux as the feedback device is displaced along the longitudinal axis.
4. The feedback assembly of claim 3, wherein the at least one sensor is mounted adjacent the feedback device between the first edge and the second edge, the first end of the at least one position marker extending laterally beyond the first edge and the second end of the at least one position marker extending laterally beyond the second edge.
5. The feedback assembly of claim 3, wherein the at least one sensor is mounted adjacent a given one of the first edge and the second edge, the at least one position marker extending laterally beyond the other one of the first edge and the second edge.
6. The feedback assembly of claim 2, wherein the feedback device comprises at least one support member configured to extend away from the at least one of the first edge and the second edge and to support the at least one of the first end and the second end thereon.
7. The feedback assembly of claim 2, wherein the at least one of the first end and the second end is substantially parallel to the corresponding at least one of the first edge and the second edge.
8. The feedback assembly of claim 1, wherein the at least one position marker comprises a first plurality of projections extending from the root surface and oriented substantially parallel to the longitudinal axis and at least one second projection extending from the root surface and positioned between two adjacent first projections, the first plurality of projections circumferentially spaced from one another and the at least one second projection disposed on the root surface at an angle relative to the first plurality of projections, and further wherein the first plurality of projections and the at least one second projection extend laterally beyond the at least one of the first edge and the second edge.
9. An aircraft-bladed rotor system, comprising:
- a rotor rotatable by a shaft about a longitudinal axis, the rotor having blades with adjustable blade pitch angle; and
- a feedback device coupled to rotate with the rotor, the feedback device having a root surface having an edge, at least one position marker extending from the root surface and extending laterally beyond the edge.
10. The system of claim 9, wherein the root surface has a first edge and a second edge opposite the first edge, and the at least one position marker extends axially along the root surface from a first end to a second end, at least one of the first end and the second end extending laterally beyond a corresponding at least one of the first edge and the second edge.
11. The system of claim 10, further comprising at least one sensor mounted adjacent the feedback device, the at least one sensor configured to detect, as the feedback device rotates about the longitudinal axis, a change in magnetic flux caused by passage of the at least one position marker in a sensing zone of the at least one sensor, the at least one of the first end and the second end extending laterally beyond the at least one of the first edge and the second edge resulting in an increase in a density of the magnetic flux as the feedback device is displaced along the longitudinal axis.
12. The system of claim 11, wherein the at least one sensor is mounted adjacent the feedback device between the first edge and the second edge, the first end of the at least one position marker extending laterally beyond the first edge and the second end of the at least one position marker extending laterally beyond the second edge.
13. The system of claim 11, wherein the at least one sensor is mounted adjacent a given one of the first edge and the second edge, the at least one position marker extending laterally beyond the other one of the first edge and the second edge.
14. The system of claim 10, wherein the feedback device comprises at least one support member configured to extend away from the at least one of the first edge and the second edge and to support the at least one of the first end and the second end thereon.
15. The system of claim 10, wherein the at least one of the first end and the second end is substantially parallel to the corresponding at least one of the first edge and the second edge.
16. The system of claim 9, wherein the at least one position marker comprises a first plurality of projections extending from the root surface and oriented substantially parallel to the longitudinal axis and at least one second projection extending from the root surface and positioned between two adjacent first projections, the first plurality of projections circumferentially spaced from one another and the at least one second projection disposed on the root surface at an angle relative to the first plurality of projections, and further wherein the first plurality of projections and the at least one second projection extend laterally beyond the at least one of the first edge and the second edge.
Type: Application
Filed: Mar 20, 2019
Publication Date: Sep 24, 2020
Patent Grant number: 10829201
Inventor: Dana TOMESCU (Brampton)
Application Number: 16/359,276